The PIAAs are not any brighter (same wattage), and a waste of time (yours) to install and money (yours) to buy. You also lose the adjustability of the stock fog lights.

And that is the main difference -- the PIAAs are driving lights; the stock lights are for fog -- which means better beam spread. However, if you use that stock adjustment screw, and crank the beam just high enough to be at the top of the normal headlight pattern (use a white wall) -- you will have virtually the same performance, for $16.00 and zero installation hassle.